I was digging around YouTube and came across this. (a) The director decided not to reuse any themes from the Goldsmith score from Star Trek: The Motion Picture. That’s not really explained. And (b) the director wanted a “seafaring” sound. So yes, the score sounds very British, and closing your eyes you can almost hear it working well in “Master and Commander” (though the Horner theme is perhaps a bit too heroic for that).